Moldboard plow with plastic resin covering



Nov. 17, 1959 Filed Nov. 2s. 195'? R. R. 'QWEN TAL 2,913,060

MoLDBoARD'PLow WITH PLASTIC RESIN covERING 2 Sheets-Sheet 1 Nov. 17, 1959 R. R.. owEN ErAL MoLDBoARD PLow WITH PLASTIC REsINbovERING Filed Nov. 25. 195'? 24 l f Z6 nited States patent MoLDBoARD PLOW WITH PLASTIC RESIN covERlNG l Robert R. Owen, Birmingham, Mich., and .lohn F. Cykler and Roy T. Tribhle, Honolulu, Hawaii, assignors to APineapple Research Institute of Hawaii, Honolulu,

Hawaii, aHawaiian association Application November-7.25, 51957, Serial No. 698,754

`7 Claims. (Cl. 172 747) The present invention relates to plows useful in plowing soils which fail to scour cleanly from tillage equipment and soils which have a heavy cover of vegetative growth, plant residue, or other debris on the surface thereof. Particular application has been made to the non-scouring low humic and humic latosols of Hawaii under pineapple culture.'`

The scouring point or sticky point (Klebegrenze of `v Atterberg) represents the moisture content above which soil sticks to a foreign object. The scouring quality of soils is considered to be the result of the adhesive effect ofV water lms which is sufficient to cause the soil to adhere or stick to the surface of the ground working implement. A furrow slice which fails to'scour is not properly inverted by passage across the share. Such adhesion also markedlyincreases the kinetic friction or -resistance to passage of the soil over the share. The

moisture content at which highly plastic soils fail toA 2,913,660 PatentedVV 1959 ice It has heretofore been considered *necessary that the moldboard of the plow'be provided with mechanically movable elements, such as belt type conveyors, as shown `4in such U.S. Letters Patent. Prior attempts have been made to build moldboard plows with movable parts associated with the moldboard and 4with different materials as wood and rubber but vthey have not proven successful.

In accordance with the present invention, the construction of a moldboard plow forthesek purposes is greatly simplified `by coveringthe moldboard with polytetrafluoroethylene resin which is sold under the trademark Teflon. Teon in sheet form is used to cover a part of the moldboard where scouring diculties normally occur. Teflon is used in low pressure areas. The shin and share of the plow are high pressure areas, and, therefore, scour and do not require the Teflon covering.

It is, therefore, a general object of the present invention to provide an improved plow'for thesepurposes. f v

Another object of the present invention is tof provide a moldboard plowE that has proven successful in plowing non-scouring soils of the type found in Hawaii.`

Another object of thepresent invention is to provide an improved moldboard plow in which no'movable parts are associated with the moldboard for purposes of maintaining the moldboard clean of non-scouringsoils.

Another object of the present linvention is to provide 'an improved plow'which has selected portions thereof covered `with a plastic resin that repels waterI very strongly 1 p Y n 5 Another object of the V'present invention `is to provide an improved plow constructed sothatit may Voperapproximately 85% clay separates. lDespite the high kaolin clay mineral in this fraction, the soils areimoderately to highly plastic, for their plastic index lies between 10 and 20. Soil with a plastic index greater than 15 is considered highly plastic. Moreover, lthe lower plastic limit of thesesoils is frequently-a moisture content less than the moisture equivalent and the "field capacity. As aconsequence, these soils' oftenfail to scour cleanly and have a very high coelcient of kinetic friction when at the appropriate moisture content." One of the major design 'variables of tillage equipment is the composition and polish of the material of the `surface applying the force to the soil. Non-wetting material with a low coeicientof friction will insure scour and decrease the kinetic friction `across the share. This action will ensure proper inversion of the furrow and decrease the power required to operate the equipment.

The moldboard plow has long been recognized, where scouring conditions exist, as the most ecient 'plow type known; however, problems are encountered'in the Vuse of such moldboard plow, particularly in the pineapple industry in Hawaii which requires a moldboard plow to invert the soil and bury trash in order to prepare the fields properly. Much time and effort has heretofore been expended in developing such a moldboard plow and many different expedients have been tried, as shown and described-in`U.S.Letters Patent of Arnold BfSkromme, No. 2,689,512, which lis assigned to the present' assignee. The problems encountered in properly working Hawaiian soils is also explained in sucli Patent No. 2,689,512.

ate in smallerV fields; `rback up to sharp cornersj'and work in rougherterrainand-which allows "the useiof smaller tractors to f plow the 'same ydepth over the vsame width at the same tractorV speed; or to obtain greater plow depth, additional-"plow fwidth 'or greater speed using'present tractors! v v i The features of the present invention which are believed to-be novel are set forth withA particularityrin the appended claims. "This invention itself, bothes t0 its organization.` and manner offoperationtogether:with further objects -and. advantages thereof, vmay be best understood by reference to the following description taken in connection with the accompahying drawings in which: r H Y Figure l isa perspective view showing vav plow 'embodying features of the present invention mounted on a tractor.

Figure 2 is a view taken generally in the direction indicated by the arrows 2 2 in both Figures l and 3.

Figure 3 is a sectional view taken along the line 3 3 inFigure 2. l L

Figure 4 is a top view taken generally in the direction indicated by the arrows 4 4 in Figure 3. f

Figure 5 is a sectional view taken along the line 5 5, in Figure 4.-

The moldboard plow 10 is pulled by the tractor 11 and has its` beam 12. adjustably secured 4to the conventional U-shaped plow hitch 13. The U frame is lifted hydraulically to clear the ground in the transport position. For these purposes, a clevis type structure 15 is bolted on the hitch. frame 13 and has a plurality of vertically spaced holes 15Av through' which fastening bolts 18 extend for adjustable securing of the plow beam Y12. on the hitch 13.

The plow beam 12l1'as a downwardly extendingleg 12A to which is-welded an arcuate shaped plate 20 havgroundV engaging or depth control wheel 22. lThe wheel r 22 is rotatably supported on an axle 23 which is welded on an arm 24, such arm 24 being pivotally mounted on the downwardly extending beam portion 12A at 26. The arm 24 is releasably secured to the plate 20 by a bolt 28 which passes `through Vaperturetl rportionY 20A in bolt 20 and the apertured portion of arm 24.

The plowing portion of the plow is pivotally mounted on the beam 12 by the axis of the bolt 30`which passes through apertured portions of the spaced beam members 12C and 12D and the plow supporting arm 32. Such arm 32 is normally prevented from pivoting, however, while plowing, by means described later.

The arm'32 at its lower endhas bolted thereto the landside plate 35 by means of bolts 36. The frog assembly 37 iswelded to the landside plate 35 and elements 'thereof are secured by brace members 3S and 38A. Such frog assembly includes the landside plate 35, the wing section 42, moldboard 39 andthe plow tip 44.` The plowshare 45 comprises a plate which is detachably'secured to the frog assembly and it, with the plow tip 44, denes the lower portion of the plow.

In accordance with the present invention, at least a portion of the earth engaging side of the moldboard 39, is covered with a strip of Teflon 46 and such Teon may be secured by conventional fastening means such as bolts. A shin guard 47 should be secured to cover a substantial portion of the upper leading edge of the moldboard when pressures are high. Further, such shin guard may be secured such that it overlaps the upper leading edge of the Tellen strip 46 as to protect and secure the same in position. The term Teflon is used in a generic sense and could include cementable Tetlon sheets that are cemented on the moldboard such as, for example, sold under the name of Kalou-T by Shamban Engineering Co., of Culver City, California.

These soils are low in quartz content and are, therefore, slightly abrasive to plastics such as Teflon. Even though it has been found that non-compounded'Teflon withstands the abrasive action of Hawaiian soils, it is considered desirable to use Teiion compounded with glass fibres instead of non-compounded Teilon.

Plowing is accomplished at depthswofl approximately 18 and greater. In order to provide some protection against buried rocks, the plowing portion of the plow is allowed to pivot about the axis ofthe` bolt 30 when an obstruction such as a rock is encountered. Normally, a shear bar 50 having its lower end disposed between shearing anvils 51 and 53 prevents pivotal movement. The anvil 51 forms a part of the beam` portion 12A and the anvil 53 is a shoulder on the landside plate 35.v As shownin Figure 3, the shear bar 50 is positioned between the anvils 51 and 53 and prevents counterclockwise pivotal movement of the plowing portion ofthe plow.l However, whena large obstruction is encountered, the shear bar 50 is sheared between anvils 51 and 53 and during subsequent'pivotal movement of the landside plate 35, the lower cut end of the shear bar 50 bears against the circular shear bar supporting plate 60 which is mounted on the landside plate 3 5. The shear bar 50 may be moved in its space guides 62 and 63 on the beam portion 12A so that it may slide therein under the influence of gravity force or under the influence of a spring (not shown) when the plowing portion is pivoted back to its normal position, at which time the shear bar 50 is automatically positioned as shown in Figure 3, between the anvils 51 and 53.

l While the clevis structure that serves toi mount the beam 172'on the tractor hitch 13 affords: the same vertical adjustment, more precise adjustment is desirable and this is accomplished by adjusting the position of the wheel axle supporting arm 244 with respect to the apertured plate 20.`

IIt is noted thatthe landside plate 35 is constructed oxfumild steel havingathckness of approximately 1172".

Such plate 35 has adjustably secured, on its outer side, a suction controlling plate 35A. Shims of variable thicknesses are interposed between the plates 35 and 35A to adjust the landside suction and direction of pull. The moldboard backing plate 39 may be of sheet material having a thickness of approximately Vj and of mild steel. Physically, the moldboard plate 39 is formed as a generally hyperbolic-paraboloid shape. It is noted also that the detachable plowshare plate 45 overlaps a portion of yt'heleading lower edge of the Teflon sheet 46 so that such plate 45 and the shin guard 47 overlap and firmly secure the leading edges of the Teon 46 to secure and protect same. As explained before, the plowpoint 44 is an integral part of lthe frog assembly and is not detachable. Using this structure wherein the point of the plow is an integral part of the frog, a minimum of bracing is required for the wing section.

Thus, it is noted that the plow is designed to penetrate the soil and plow a straight furrow. Its narrow, gentle angle shim is responsible for the soiljcompression necessary for shear action, while the vmoldboard lifts the sheared soil on a gentle incline and sets the inverted soil aside. The soil thus inverted buries trash so that the lields are properly prepared. The soil will not adhere to the Teon on the moldboard and will scour from the moldboard.

The provision of the Tellon coating 46 on the moldboard is of extreme importancein achieving successful operation. Teiion is a soapy feeling plastic and the addition of the same to the moldboard permits the operation of a strandard moldboard plow in Hawaiian soils. Teflon may be characterized chemically as a polymer formed from a monomer having the structure:

where R1, R2, R3, and R4 represent uorine.

While successful results have been obtained with Teflon and polyethylene, other materia-ls having the same chemical structure, as characterized above, may be used where the R1, R2, R3 and R4 are constituents selected from the group in which R1, R2, R3, and R4 are hydrogen, chlorine, iluorine methyl, and cyanide. Such chemical compounds are, for example, the rst, second, third, ninth and twelfth of the compounds listed on pages 82 and 83 and the compound shown on page 98 of the Scientific American of September 1957. These com pounds are, namely, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride and polytriiluorochlorethylene.

While the particular embodiments of the present invention have beenv shown and described, it will be obvious to thoseA skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

We claim:

l. A moldboard type plow having a Vfrog section that comprises a landside member, a plow tip integrally formed with said member, a removable share mounted on at the lower portion of said frog section, a removable shin mounted on said frog section at the leading edge of the same, said plow having a moldboard, a layer of polytetrauoroethylene mounted on said moldboard, said layer being shaped to conform with the surface thereof and secured thereto by having edges thereof overlapped by said share and shin.

2. A moldboard type plow for use in non-scouring soils having at least a portion oi its moldboard covered with a layer of a polymer formed from a monomer having the structure where R1, R2, R3 and R4 are each selected from the group consisting of fluorine, hydrogen, methyl and chlo rine, said layer of polymer being shaped to conform to the surface of said moldboard and being secured thereto.

3. A moldboard type plow as set forth in claim 2 in which R1, R2, R3 and R4 are each iluorine.

4. A moldboard plow as set forth in claim 1 in which said member carried an adjustable plate for adjustment of horizontal suction forces developed While plowing.

5. A moldboard plow having at least a portion of its moldboard covered with a layer of a polymer formed from a monomer having the structure where R1, R2, R3 and R4 are each selected from the group consisting of fluorine, hydrogen, methyl and chlorine, said layer of polymer being shaped to conform to the surface of said moldboard and being secured thereto, and removable means mounted on the leading edges of said moldboard which overlap edges ofrsaid layer and compress said edges between the moldboard and said removable means to secure and protect the same.

6. A plow as set forth in claim 2, inwhich said polymer is cemented on the moldboard of the p'low.

7. A plow as set forth in claim 2 in which said polymer is compounded with material such as glass bers to increase its wear resistance.

References Cited in the le of this patent UNITED STATES PATENTS 1,058,248 Martn et a1. Apr. 8, 1913 1,280,088 Saltzer Sept. 24, 1918 1,303,432 Weisenborn May 13, 1919 2,768,925 Fay Oct. 30, 1956 2,773,781 Rodman Dec. 11, 1956 

